Various structures require two separated parts to become bonded. For example, substrates may need to be bonded in many different scientific, technological and industrial applications. There still remain certain issues in the standard techniques for bonding various substrates. For example, conventional techniques of bonding substrates may lead to residual stresses left behind in the bonding process. Moreover, the bonding process may lead to limits in the maximum operating temperatures of the bonded materials. This can be difficult since too much heat can overheat and destroy delicate components. That in turn may weaken the substrates, or may undesirably diffuse bonded materials into the substrates. Finally, small size bonding techniques may be difficult.
The present application teaches bonding structures using the selective heating feature of microwave energy. A low temperature, low pressure wafer bond, can be effected. According to the present system, first and second substrates may be bonded. The first substrate material has a first surface material part and the second substrate material has a second surface material part. The two parts are aligned. Microwave energy is applied to selectively heat the material parts in order to bond the first substrate to the second substrate. The substrates can be any material that is a poor absorber of microwaves, while the substrate surface material can be any material that is a better absorber of microwaves than the substrate. For example, the substrates may be insulators, semiconductors or the like, while the substrate surface material can be a metal.